According to Childe, agriculture developed rapidly, hence the term Neolithic Revolution, and thus was synchronous with the onset of dry conditions that climate records were suggesting in the Near East at the end of the Pleistocene. To survive, humans and potential domesticates concentrated together in well-watered locations like oases and river valleys, where their close interactions naturally led to domestication and ultimately agriculture. The discovery of sickle blades and grinding stones in the Carmel Caves of coastal Palestine suggested that hunter gatherers collected wild cereals during the Natufian Period , evidence used by Childe in support of this idea . Although propinquity is overly simplistic , subsequent paleo environmental and archaeological work suggests that regionally specific climatic and biotic changes did occur at the end of the Pleistocene. These surely played a role in shaping spatially local cultural developments, including the domestication of plants and animals and ultimately the adoption of agricultural practices . Unfortunately, the overly deterministic nature of the Oasis Theory also provoked a backlash in the broader archaeological community against the importance of changing environmental conditions during the Late Pleistocene and Early Holocene . For many years the role of climate change was simply ignored or deemphasized relative to other mechanisms perceived to have greater explanatory value. With several noteworthy exceptions , container size for raspberries this continues today, even with the development of sophisticated paleo environmental techniques and the aggressive advance of earth system science and high resolution climate records . These records show that the domestication of key cultigens in the Old and New Worlds occurred during an interval marked by significant fluctuations in global climate .

Environmental change at the end of the Pleistocene was most pronounced at higher latitudes as ambient air temperature increased, glaciers receded, sea-levels rose, and forests replaced periglacial tundra . Dramatic fluctuations in high latitude environmental conditions parallel substantial changes in temperature and rainfall regimes at lower latitudes . Some regions witnessed the extinction of several large animals, a likely product of environmental change and intensified human predation at the end of the Pleistocene . Others experienced the expansion of wild plant species that were intensively harvested by foragers and, through selective manipulation, became important cultigens . It is under these dynamically changing environmental conditions that foragers altered their subsistence regimes and made dietary choices that led to plant and animal domestication, low-level food production, and ultimately agriculture.Endogenous social change, particularly the development of prestige economies via socioeconomic competition, has recently become a popular explanation for the transition to agriculture . The mechanism for change in these models is status-seeking individuals, usually men, who encouraged and controlled the growth of potential domesticates to create surpluses for social purposes such as competitive feasting, alliance formation, and extortion, rather than as primary sources of food. Hayden has been the most outspoken advocate of this idea as a general explanation for the transition to agriculture worldwide—from the earliest plant and animal domestication through the development of more intensive forms of food production. Hayden’s model is based on five testable hypotheses : domestication and agriculture will emerge in resource-rich, not resource-poor, zones; it will first develop in ranked societies that have marked status inequalities; individuals within these societies will hold competitive feasts; the first plants and animals domesticated will be intoxicants, delicacies, or prestige goods rather than bulk or mundane food items; and evidence for resource stress and malnutrition caused by population pressure or climate change will be absent.

In archaeological terms Hayden’s scenario implies correlation between plant and animal domestication and agricultural development, and the emergence of socioeconomic complexity, marked archaeologically by a high degree of sedentism , at least two-tiered settlement hierarchies, intensified production agriculturally or otherwise, storage, specialized production of prestige items or status markers, intensified exchange, acquisition of exotic items by elites, and differential distribution of prestige items in households and burials. There are several fundamental flaws with the socioeconomic competition model; there are also some intriguing and potentially important insights. As a stand-alone model for agricultural origins, socioeconomic competition fails on two levels. First, it lacks a unifying explanation for why agriculture developed in several independent regions at approximately the same time—other than suggesting it was a historical accident . Second, although there is evidence that agriculture often developed in resource-rich habitats , the initial domestication of most plants and animals occurs well before conditions promoted socioeconomic competition, at least in Asia, Africa, and the Americas . It appears that many domesticates in Mesoamerica, the Near East, and eastern North America were used by hunter-gatherers at a low level for thousands of years prior to their intensified use . This hints that socioeconomic competition is more likely to be significant in the later stages of the transition. The social significance of food is patent. That some plant species might initially have been grown to brew beer is intriguing; the social aspects of drinking intoxicating liquids are difficult to refute . However, plants used to brew intoxicating liquids can also serve as valuable food items whether they are fermented or not. This means that multiple currencies must be considered when resource value is assessed by archaeologists.

The ability to store surplus food must also be analyzed for its social significance. Individuals who successfully grow, store, and defend food items can use these stores to their social advantage, gaining prestige and influence. Use of surplus food to improve social advantage, at least under certain environmental and demographic conditions, should be examined by scholars employing HBE models.There is a small HBE literature on agricultural origins. Keegan made an early and prescient argument that foraging models could be extended to the study of horticultural production. He highlighted horticulture because it represents a mixed subsistence system, transitional between the economies of hunter-gatherers and agriculturalists. Using data from the Machiguenga of Peru, Keegan argued that the key variables of the diet breadth and patch-use models have direct analogs in food production, facilitating the use of these cost-benefit models in analysis of this system and the evolutionary transitions that gave rise to it. His calculations showed that the Machiguenga generally were stocking their gardens with optimal combinations of cultigens and, with allowance for seasonal and nutritional constraints, making effi- cient trade-offs among fishing, forest hunting, and gardening. In a 1991 paper, Layton et al. described a “complete break” from the standard, evolutionary progression theories of agricultural origins. They proposed instead an approach that sees hunting, gathering, herding, and cultivation as alternative strategies of subsistence that may be taken up alone or in various, stable combinations, depending on socio-ecological circumstances, and without any implication of irreversible directionality to transitions among them. For instance, there is nothing to prevent food producers from evolving into foragers. Various conceptual elements from foraging theory, such as the ranking of resources by pursuit and handling costs, cost-benefit analysis of subsistence trade-offs, boundary defense, and risk minimization are found throughout their argument. In support of their interpretation they summarized numerous ethnographic cases in which these strategies are mixed in shifting and sometimes stable balances, big plastic pots reminiscent of Smith’s concept of low-level food production. Layton et al. stimulated two follow-up papers, both of them making more explicit use of foraging theory to critique or amend specific predictions from their article. Hawkes and O’- Connell used a sharper distinction between search, and pursuit, and handling times—the central conceptual distinction of the diet breadth model—to argue that high-ranking resources will not drop out of a forager’s diet in response to exploitation and depletion. However rare, they will always be pursued when encountered. Hawkes et al. expand discussion of the circumstances likely to promote subsistence innovation, and argue that “increases in diet breadth result from reduced foraging return rates and so lead to declines in population growth rates” . They also draw attention to HBE arguments for a gendered division of labor that might have been important in the evolutionary processes underlying subsistence transitions. In a second follow-up paper, Winterhalder and Goland addressed the population growth prediction by Hawkes and O’Connell, cited just above. They used a dynamic, population ecology variant of the diet breadth model to show that declining foraging efficiency associated with expanding diet breadth may result in a decrease or an increase in forager population density. The deciding factors are the density and reproductive potential—together, the sustainable yield—of the low-ranking resources that happen to come into the diet. Subsequently, Winterhalder and Goland expanded on these arguments for using a HBE form of analysis in agricultural origins research. They cited three advantages that distinguish HBE from other research traditions: it engages selectionist explanations that are more powerful than the more commonly used functionalist ones; it has tools for non-normative analysis of unpredictable variation in environmental features and the risk-minimizing adaptive tactics they elicit; and it focuses on localized and immediate resource decisions and their consequences for people “on the ground.” HBE thus engages the behaviors most likely to be causal to evolutionary change: “The changes we summarize under broad concepts such as domestication and the Neolithic revolution have their origin and form in the ecologically situated choices and actions of individuals” . Winterhalder and Goland used the diet breadth model to show how foragers might initially come to exploit the organisms that became domesticates, and to speculate on the adaptive consequences of this co-evolutionary engagement.

Among the effects examined were the consequences for resource depletion, human population density, and risk management tactics, using evidence from eastern North America to exemplify their arguments. Working on the prehistoric development of agriculture in eastern North America, Gremillion used diet-breadth and risk-minimization models along with opportunity-cost arguments to generate and evaluate predictions about the circumstances in which new cultigens will be adopted by groups already practicing some agriculture, and whether they will replace existing plant resources, as did maize following a signifi- cant delay from its first appearance, or become a supplement, as in the case of peaches. In a second study, Gremillion analyzed macrobotanical data from the Cold Oak rock shelter in eastern Kentucky to show that increased dependence on cultivation of seed crops around 1000 BC was accompanied by greater anthropogenic disturbance of habitats and a shift in mast resources from acorns to hickory nuts. She developed several HBE hypotheses to address this situation, finding greatest credence for the idea that an increase in the overall abundance of mast resources led to specialization on the most profitable species, in this instance hickory, at the expense of the less highly ranked oak. Alternatively, increases in the ranking of profitability of seed crops such as maygrass, chenopod, and knotweed may have displaced acorns from the diet due to their high processing costs. In each of these applications Gremillion argued that HBE is a fertile source of new and archaeologically testable hypotheses about the subsistence and economic changes associated with the origins of agriculture. The most thorough existing application of HBE to the question of agricultural origins is Piperno and Peasall’s monograph, The Origins of Agriculture in the Lowland Neotropics. Over half the crop plants domesticated in the Americas are thought to have wild progenitors native to neotropical lowland habitats. Among them are New World staples such as manioc, yams, achira, sweet potato, peanut, gourds, squashes, beans, and perhaps maize. These plants likely were first used by foragers, who cultivated, domesticated, and subsequently incorporated into specialized agricultural production systems, in seasonal, low elevation forested habitats of the neotropics. Piperno and Pearsall focus their analysis on the climate and vegetation changes occurring at 11,000 to 10,000 radiocarbon years BP and their likely effects on Neotropical foragers. The first inhabitants of the neotropics encountered a salubrious, open-grassland foraging environment that persisted for only a short time. At around 10,500 BP, the transition to a wetter Holocene climate began to produce a seasonal, deciduous forest cover in the lowland tropics. Piperno and Pearsall hypothesize that due to this habitat shift, and perhaps also to human exploitation , the abundance of the high ranking, “open habitat,” plant and animals species decreased, along with foraging efficiency. While the new seasonal forests remained relatively hospitable to mobile hunter-gatherers at low population density , the diets of early Holocene foragers expanded to encompass a broader array of dry-forest plants, species that previously had been ignored. For instance, comparative studies of the efficiency of harvesting tubers suggest they likely were outside of the optimal diet in the late Pleistocene , but moved into that diet as a low-ranked but critical resource once early Holocene habitats became more forested.